BRCA1 is a tumor suppressor gene that is a key factor in responding to DNA damage. Mutations or deregulated expression of breast cancer susceptibility gene 1 (BRCA1) are associated with a significant increase in breast cancer as well as ovarian, cervical, uterine, pancreatic, colon, testicular and prostate cancers as well as melanomas.
Even with improved diagnostic techniques and treatment, cancer remains one of the leading causes of death. Excluding cancers of the skin, breast cancer is the most common cancer diagnosed among U.S. women, accounting for more than 25% of the cancers. Breast cancer is the second leading cause of cancer death in women, after lung cancer. The American Cancer Society (ACS) estimates that in 2009 an estimated 192,370 new cases of invasive breast cancer will be diagnosed among women and 1,910 new cases among men. The ACS also estimates that 40,170 women and 440 men are expected to die from breast cancer.
Between 5-10% of breast cancer patients have an inherited mutation(s) in BRCA1. The remaining 90-95% of breast cancer patients have the sporadic form of the disease. Although decreased expression of BRCA1 is a good indicator of breast cancer and its prognosis, a major difficulty is accurately measuring the levels of BRCA1 in cells. In addition, the levels of BRCA1 can assist a health care provider in determining the type of therapy to be utilized to assist a patient. Accordingly, improved methods of determining the levels of BRCA1 in a cell are urgently needed.